Our objective is to determine the long-term sequelae of administration of opiates and other drugs of abuse to parents, prior to mating, upon the development of subsequent progeny and to elucidate possible mechanism(s) for this effect. Our previous studies have demonstrated that premating administration of morphine to male or female rodents results in an attenuation of analgesic response among first generation offspring and retardation in growth of the three generations of progeny observed to date. We wish to extend these observations and study in detail the behavioral processes affected by this early exposure to morphine. The effect of premating morphine administration to rodents on several behaviors will be studied to permit the development of a behavioral profile which can provide a more adequate evaluation of the consequences to the central nervous system of the premating administration of opiates. Behaviors studied in offspring will include ontogeny of reflexes, exploratory and spontaneous activity, maze learning, response to opiates on a foot-shock-titration analgesic procedure, response to various reinforcement schedules and to intracranial reinforcement. Cross-fostering procedures will be employed to evaluate the role of pre-and postnatal influences on the behavior under study. To determine whether the long-term effects of premating administration morphine are unique to opiate and other dependence-producing drugs, the effect of barbiturate and phenothiazine adminstration prior to mating on physical growth and behavior of offspring will be explored. Cytogenetic study of chromosome morphology and mitotic rates of offspring will be continued to evaluate the role of genetic influences.